Why it matters
Browser projects often need better control over line wrapping, text segmentation, and layout prediction than default text rendering alone can provide.
Library Guide
What is Pretext?
Pretext is a JavaScript and TypeScript library for multiline text measurement and layout. This page explains what the library does, where it comes from, and how the Pretext platform uses it to build browser games and interactive text experiments.
TYPE
JavaScript and TypeScript text layout library
ROLE
Measures and prepares multiline text for rendering and interaction
SOURCE
Official project by chenglou on GitHub
THIS SITE
Independent guide and project platform built with the library
Definition
Pretext solves the hard part of multiline text layout before you render the final experience.
In practice, that means Pretext helps prepare text lines, measure layout behavior, and organize segments so developers can build text-aware interfaces instead of treating text as passive decoration.
What it enables
Pretext is useful for browser games, Canvas interfaces, custom typography systems, text visualizations, and interactive experiments where text layout affects behavior.
What this page is for
This page exists to explain the library clearly and connect that explanation to real project examples on the Pretext platform.
Relationship
The library and the platform are related, but they are not the same thing.
Dimension
Pretext Library
Pretext Platform
Owner
Official open source project by chenglou
Independent platform built with the library
Purpose
Provide text measurement and layout capabilities
Show what can be built with those capabilities
Output
Library APIs and layout behavior
Playable browser projects and case studies
Current examples
General-purpose text layout logic
Text Invaders, Text Pong, and Text MDR
Examples
The strongest way to understand Pretext is to see how it behaves inside real products.
The Pretext platform currently demonstrates the library through three browser games. They share a platform identity, but each one exposes a different aspect of text-first interaction design.
Text Invaders
Text Invaders shows how live text can become enemies, geometry, and dynamic reflow behavior in a browser game.
Text Pong
Text Pong shows that the same platform and visual system can support a different arcade loop without losing the text-first identity.
Text MDR
Text MDR shows how the same library can support dense dossier-based refinement, anomaly tracking, and slower, strategy-leaning text play.
Future examples
As the platform grows, more games, text demos, and browser-native experiments can become examples of what Pretext enables in practice.
FAQ
Short answers for people searching for Pretext.
What is Pretext?
Pretext is a JavaScript and TypeScript library for multiline text measurement and layout. It helps developers prepare and position text before rendering it into interactive browser experiences.
Is this the official Pretext website?
No. The official open source project is the GitHub repository maintained by chenglou. This site is an independent platform and guide built around projects that use the library.
What can be built with Pretext?
Pretext can support browser games, custom typography systems, Canvas-based interfaces, text experiments, and tools that depend on accurate multiline text layout and measurement.
Where can I see real examples?
The Pretext platform currently offers Text Invaders, Text Pong, and Text MDR as three playable browser examples built on top of the library.